Similar to a fuse the mech hanger is designed to keep the worst from happening to your derailleur in the event of a crash. Keep one or two on hand if you are planning big!
1x mech hanger
This article consists of only the mech hanger. Should you be looking for a set including both the hanger and the screw see here.
The mech hanger is fitting for:
JEFFSY MK1 CF 2016 - 2018
JEFFSY MK1 AL 2016 - 2019
CAPRA MK2 2018 - 2021
Art. Nr. 500768